You can find a maid or even a mate online, but parents are understandably cautious when it comes to babysitting. There's an added sense of comfort that comes with knowing the sitter's parents when you tear that phone number off the bulletin board at the gym.

It's Lynn Perkins' job to make hiring a sitter through a website feel safe as well as easy. She's the co-founder and chief executive officer of UrbanSitter, a 20-employee San Francisco startup that's trying to snag a piece of the fragmented $47 billion U.S. child care business with its online marketplace.

The company has facilitated more than 170,000 babysitting jobs since its 2011 founding, mostly in San Francisco and New York. Last week it announced that it raised $15 million in funding led by DBL Investors, a venture capital firm that spun out of JPMorgan Chase, and Match Group, IAC's dating site division

UrbanSitter's roughly 70,000 member parents log on to its website or mobile app with their Facebook accounts and enter the name of their child's school and any clubs he or she has joined. They can then see reviews of some of the 30,000 sitters from friends and others in their social circles.

Sitters typically charge $10 to $30 per hour. If a favorite is busy, parents can browse among that caregiver's friends who are looking for jobs on the site. Parents can also see how often each sitter gets repeat customers. Like many startup founders, Perkins compares her company to car service Uber and home rental site Airbnb, though she acknowledges that she'll have to meet higher standards.

"It's one thing when you have an Uber driver who is only so-so," said Perkins, who previously founded the fashion site Xuny.com. "We know our primary challenge is to build a marketplace that parents can trust."

Perkins' site makes money by charging fees, including $15 that parents pay when they book a particular sitter for the first time. Caregivers can place their profile and accept jobs on the site for free, but must pay monthly fees (or an annual charge of $70 to $100) to rank higher in the site's search results and show that they've passed a background check. Rachael Norman, a Stanford University graduate who babysits for $20 an hour while hunting for a job at an Internet company, said UrbanSitter has helped her pack appointments into her schedule. "For somebody who allows herself to be available 40-plus hours a week, this can be a living," she says.

UrbanSitter has some well-funded competition. Care.com is an 8-year-old company with a marketplace that includes care for seniors, pets and homes as well as kids. It went public in January and raised $105 million on its way to a market valuation of more than $800 million. Cynthia Ringo, managing partner of DBL, said there's room for Perkins to carve out a niche in babysitting, then "to expand to other areas where you want a trusted provider." Care.com, which is in a post-IPO quiet period, declined to comment.

Perkins, a mother of three, says the new funding will let UrbanSitter, which isn't profitable yet, grow stronger outside San Francisco and New York. The fees may turn off sitters who need every buck, and some parents may prefer to choose from neighborhood teenagers. (Sitters on the website must be 18 or older.)

For newcomers to a city, however, Perkins' site can yield quick connections, and for parents, it's hard to overstate the value of a short-notice sitter. When parents post a job request, Perkins said, the median response time is less than two minutes.